Endless track assembly for supporting an implement or vehicle

ABSTRACT

A track assembly includes an elongated main frame supported for pivotal movement on a transverse axis and having opposite end portions supporting a set of end wheels. An endless flexible belt extends around the end wheels and has an upper run and a lower run for engaging the ground. A plurality of longitudinally spaced bogie wheels are positioned below the main frame and engage the lower run of the belt. The bogie wheels are carried by bogie frames supported for vertical movement and also for tilting movement relative to a plane defined by the axes of the end wheels. The bogie frames are urged or biased downwardly against the lower run of the belt by compression members extending from the main frame and preferably in the form of annular rubber spring members.

BACKGROUND OF THE INVENTION

This invention relates to an endless track assembly for supporting animplement or vehicle, such as, for example, of the general typedisclosed in U.S. Pat. No. 7,380,892, U.S. Pat. No. 7,726,749 and U.S.Pat. No. 9,440,691. In such a track assembly, it is desirable for thetrack assembly to accommodate uneven loading across the track assemblywheels, including the end wheels for the endless track or belt and thesmaller bogie wheels which engage the bottom or lower run of the endlesstrack or belt. It is also desirable to provide more uniform groundcontact over uneven terrain in order to minimize stresses and vibrationsin both the track assembly components and in the implement or vehiclesupported by the track assembly. The decrease in stresses and vibrationin an implement being supported by the track assembly also reduces anydiscomfort to the driver of a tractor or vehicle that is pulling theimplement supported by the endless track assembly.

SUMMARY OF THE INVENTION

The present invention is directed to an improved endless track assemblywhich provides the above advantages by using a floating suspension forthe bogie wheels which are biased downwardly so that the wheels moreclosely follow the contour of the ground or uneven terrain. This isprovided by downward compression on the bogie wheels along with pivotingor tilting movement of the wheels in both longitudinal and transverseplanes on longitudinal and laterally extending axes. As a result of thefloating and tilting bogie wheels with vertical and pivotal movement,the endless track follows the contour of the terrain more closely andthereby reduces ground pressure and soil compaction. The suspendedfloating support of the bogie wheels also distributes the combinedweight of the track assembly and the supporting implement or equipmentmore uniformly over the ground contact area of the endless track or beltand further extends the service life of the endless track and theimplement or equipment.

Other features and advantages of the invention will be apparent from thefollowing description, the accompanying drawings and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective or isometric view of an endless track assemblyconstructed in accordance with the invention and which provides theabove features and advantages;

FIG. 2 is an elevational side view of the track assembly shown in FIG.1;

FIG. 3 is an elevational view of the center frame assembly used in thetrack assembly shown in FIGS. 1 & 2;

FIG. 4 is a fragmentary view of the frame assembly with one set ofsuspended and floating bogie wheels in its upper retracted position andanother set of bogie wheels in its lower position;

FIG. 5 is a horizontal section of the frame assembly and suspended bogiewheels, taken generally on the line 5-5 of FIG. 4;

FIG. 6 is a vertical section of the frame assembly and bogie wheels,taken generally on the line 6-6 of FIG. 4;

FIG. 7 is a vertical section of the frame assembly and suspended bogiewheels, taken generally on the line 7-7 of FIG. 6;

FIG. 8 is a side elevational view of a set of bogie wheels, takengenerally on the line 8-8 of FIG. 6;

FIG. 9 is an isometric view of an assembly or set of four bogie wheels;

FIG. 10 is a plan view of the assembly of the four bogie wheels shown inFIG. 9;

FIG. 11 is a vertical section of the bogie wheel assembly, takengenerally on the line 11-11 of FIG. 10; and

FIG. 12 is an end view of the bogie wheel assembly shown in FIG. 10.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

FIG. 1 illustrates an elongated endless track assembly 20 which includesan endless flexible rubber molded belt 22, preferably of the typeproduced by Camso, Inc. in Emporia, Kans. The belt has an exteriorsurface formed by a herringbone pattern of laterally extending integralrubber lugs 23. The inner surface of the belt 22 has longitudinallyspaced integral projections or lugs 24 (FIG. 2) in the center portion ofthe belt. The endless belt 22 extends around a pair of end wheels 30 ateach end, and the wheels have hubs 32 secured by bolts to wheel bearingsmounted on opposite ends of corresponding axles 34. The axles extendthrough tubes 36 (FIG. 3) supported by opposite end portions of anelongated fabricated steel frame 40 (FIG. 3). The end wheels 30 on eachaxle 34 are spaced axially on the axle to define a space which receivesthe lugs 24 on the belt 22 to maintain alignment of the belt on thewheels.

One end portion of the frame 40 supports a bracket 44 (FIG. 3) whichcarries the tube 36 for the front axle 34, and the bracket 44 isadjustable longitudinally on the frame 40 for accommodating any stretchin the endless belt 22. The opposite or rearward end portion of theframe 40 supports a pivotal lever 48 (FIG. 3) which supports the tube 36for the rear axle 34. The forward end portion of the lever 48 isconnected to the frame 40 by a tension spring 51 and an adjustable nuton an eye bolt 53 for selecting and maintaining the desired tension inthe endless belt 22. The center portion of the frame 40 has areinforcing brace 54 and supports a cross tube 56 which receives across-shaft (not shown) secured to the frame of the implement orequipment supported by the track assembly 20. The tube 56 provides forpivoting of the track assembly 20 on a transverse or laterally extendingaxis.

Referring to FIGS. 4-12 and in accordance with the present invention, aforward set of four bogie wheels 60 and a rearward set of four bogiewheels 60 are supported below the frame 40 in suspended floatingrelation and float vertically between an upper position as shown by theforward set of bogie wheels in FIG. 4 and a lower position as shown bythe rearward set of bogie wheels in FIG. 4. As shown in FIG. 2, all ofthe bogie wheels 60 are substantially smaller than the end wheels 30 andare normally biased to their lower positions where the bogie wheelsengage the inner surface of the bottom run of the belt 22 outboard ofthe lugs 24.

Each set of front bogie wheels 60 and rear bogie wheels 60 is supportedfor independent vertical and tilting movement relative to the beam 40 bya support frame 62 (FIG. 7) including a vertical guide plate 64. Theplate 64 is rigidly connected to longitudinally extending and parallelspaced plates 68 (FIG. 7) located adjacent the inner sides of each setof four bogie wheels. The plates 68 are also connected by a pair oftubes 72 secured by bolts 73 to a pair of axles 74 having outer endportions which receive the bearings and hubs 76 (FIG. 8) for the set offour bogie wheels 60.

Each of the vertical support plates 64 for each set of four bogie wheels60 is guided for vertical and tilting movement in a verticallongitudinal plane between a pair of rollers 78 (FIG. 5) supported byinclined brackets 81 (FIG. 7) secured to the frame 40. Thelongitudinally extending parallel plates 68 projecting from eachvertical plate 64 have end portions connected by plates 82 (FIG. 10) andsupport parallel spaced opposing guide plates 83 that receivetherebetween a roller bearing 86 (FIG. 7) supported by an end bracket 87and a center vertical plate 88 for guiding the support frame 62 for eachset of four bogie wheels for both vertical and tilting movement both ina vertical longitudinal plane and a vertical lateral or transverseplane.

Referring to FIGS. 9-12, the vertical guide plate 64 of the frame 62which supports each set of four bogie wheels 60, also supports a pair ofcircular base plates 92. Each base plate receives a bottom plate of aresilient compression member 95 (FIG. 4), preferably in the form of ahollow rubber spring member such as produced by Timbren Industries Inc.of Whitby, Ontario, Canada. A top plate 96 (FIGS. 1 & 4) of eachcompression member 95 is connected by bolts to a pair of opposingL-shaped brackets 98 (FIGS. 1 & 4) having inner ends welded to the maincenter frame 40.

As apparent from the above construction of the track assembly 20, eachset of four suspended bogie wheels 60 is free to float up and down andtilt in both longitudinal and lateral vertical planes against thedownward pressure or bias produced by the rubber compression members orsprings 95. That is, the support of the longitudinal center frame 40 ofthe track assembly 20 by the cross tube 56 permits the entire trackassembly 20 to pivot or tilt in a longitudinal vertical plane on atransverse axis.

The rollers 78 contacting the vertical guide plate 64 and the rollers 86contacting the guide plates 83 permit each bogie support frame 62 andthe corresponding set of four bogie wheels 60 to move or float up anddown and also tilt forwardly and rearwardly in a longitudinal verticalplane. In addition, the rollers 86 between the vertical guide plates 83cooperate with the rollers 78 and guide plate 64 to permit each bogiesupport frame 68 and the corresponding set of four bogie wheels 60 totilt laterally in a transverse vertical plane in both directions. As aresult, the lower run of the endless belt 22 engages and follows thecontour of the ground with more uniform pressure and thereby provide allof the advantages mentioned above in the Summary of the Invention.

In addition, when the track assembly 20 is supporting a lighter load,such as an empty grain cart, the bogie wheels 60 press a portion of thelower run of the belt 22 under the bogie wheels downwardly below theportions of the belt contacting the end wheels 30 so that the bogiewheels 60 carry all of the load. As a result, the raised end wheels 30allow the belt to slope upwardly to the end wheels so that the belt moreeasily climbs over uneven terrain. The less belt contacting the groundfor a lighter load also reduces the force required to turn the trackassembly 20 and reduces tread wear of the belt 22.

While the form of track assembly herein described constitutes apreferred embodiment of the invention, it is to be understood that theinvention is not limited to this precise form of assembly, and thatchanges may be made therein without departing from the scope of theinvention as defined in the appended claims.

What is claimed is:
 1. A track assembly adapted to support an implementor vehicle and for accommodating uneven ground by improved contact withthe ground, comprising an elongated main frame supported for tiltingmovement on an axis transverse to the main frame, the main frame havingopposite end portions supporting a set of end wheels for rotation onparallel transverse axes, an endless flexible belt extending around theset of end wheels and having an upper run and a lower run for engagingthe ground, a plurality of bogie wheels each having a transverse axispositioned below a plane defined by the axes the end wheels, with thebogie wheels engaging the lower run of the endless belt, each of thebogie wheels supported by the main frame for vertical movement and fortilting floating movement relative to the plane defined by the axes ofthe end wheels, and compression members biasing the bogie wheelsdownwardly against the lower run of the endless track.
 2. A trackassembly as defined in claim 1 wherein a first set of the bogie wheelsare supported on opposite sides of the main frame by a first bogie framesupported for vertical movement and the tilting movement, and thecompression members are positioned and connected to bias the first bogieframe downwardly.
 3. A track assembly as defined in claim 2 andincluding a second set of bogie wheels supported on opposite sides ofthe main frame by a second bogie frame spaced longitudinally from thefirst bogie frame and for vertical movement and the tilting movement,and the compression members are positioned and connected to bias thesecond bogie frame downwardly separately from the first bogie frame. 4.A track assembly as defined in claim 3 wherein each set of bogie wheelscomprise four bogie wheels supported by the corresponding bogie framefor the vertical movement and tilting movement.
 5. A track assembly asdefined in claim 1 wherein the compression members are effective to biasthe bogie wheels and a portion of the lower run of the endless beltbelow the endless belt contacting the end wheels under lighter loads forreducing the force required to turn the track assembly and for reducingwear of the endless belt.
 6. A track assembly as defined in claim 1wherein the compression members comprise annular rubber springcompression members.
 7. A track assembly adapted to support an implementor vehicle and for accommodating uneven ground by improved contact withthe ground, comprising an elongated main frame supported for tiltingmovement on an axis transverse to the main frame, the main frame havingopposite end portions supporting a set of end wheels for rotation onparallel transverse axes, an endless flexible belt extending around theset of end wheels and having an upper run and a lower run for engagingthe ground, a plurality of bogie wheels each having a transverse axispositioned below a plane defined by the axes the end wheels, with thebogie wheels engaging the lower run of the endless belt, a first set ofthe bogie wheels supported on opposite sides of the main frame by afirst bogie frame for the vertical movement and for tilting movementrelative to the plane, and compression members positioned and connectedto bias the first bogie frame and the first set of bogie wheelsdownwardly against the lower run of the endless belt.
 8. A trackassembly as defined in claim 7 and including a second set of bogiewheels supported on opposite sides of the main frame by a second bogieframe spaced longitudinally on the main frame from the first bogie framefor the vertical movement and for tilting movement relative to theplane, and the compression members are positioned and connected to biasthe second bogie frame and second set of bogie wheels downwardly againstthe lower run of the endless belt.
 9. A track assembly as defined inclaim 8 wherein each set of bogie wheels comprise four bogie wheelssupported by the corresponding bogie frame for the vertical movement andtilting movement.
 10. A track assembly adapted to support an implementor vehicle and for accommodating uneven ground by improved contact withthe ground, comprising an elongated main frame supported for tiltingmovement on an axis transverse to the main frame, the main frame havingopposite end portions supporting a set of end wheels for rotation onparallel transverse axes, an endless flexible belt extending around theset of end wheels and having an upper run and a lower run for engagingthe ground, a plurality of bogie wheels each having a transverse axispositioned below a plane defined by the axes the end wheels, with thebogie wheels engaging the lower run of the endless belt, a first set ofthe bogie wheels supported on opposite sides of the main frame by afirst bogie frame for the vertical movement and for tilting movement,relative to the plane, a second set of bogie wheels supported onopposite sides of the main frame by a second bogie frame spacedlongitudinally from the first bogie frame for vertical and tiltingmovement relative to the plane, and compression members positioned andconnected to bias the first bogie frame and the second bogie framedownwardly against the lower run of the endless belt.
 11. A trackassembly as defined in claim 10 wherein each set of bogie wheelscomprise four bogie wheels supported by a corresponding bogie frame forthe vertical and tilting movement as separate units.
 12. A trackassembly as defined in claim 10 wherein the compression members compriseannular rubber spring compression members.
 13. A track assembly asdefined in claim 10 wherein the compression members are effective tobias the bogie wheels and a portion of the lower run of the endless beltbelow the endless belt contacting the end wheels under lighter loads forreducing the turning force for the track assembly and for reducing wearof the endless belt.